Heating compensating roofing boards

ABSTRACT

A roofing board, such as a polyiso insulation board, includes first and second surfaces, where the first surface is lighter in color than the second surface. This allows the roofing installer to choose which of the surfaces to expose to the atmosphere, the lighter surface being cooler than the darker surface. The lighter surface may have a solar reflectance greater than the darker surface. A roofing membrane is then adhered or otherwise attached to the exposed surface.

BACKGROUND OF THE INVENTION

Roofing boards can include particle boards, gypsum boards, or foam insulation boards. Some include facers. Others do not. Polyiso insulation boards include facers for manufacturing (foam laydown) and to provide many of the product's performance properties. The majority of facers fall into two categories: Glass Reinforced Felt (GRF) or Coated Glass Faced (CGF). GRF facers are also known as “paper” facers given their craft paper appearance. GRF facers generally range in color from light brown to darker brown and are made from fiberglass reinforced pulp paper. CGF facers, on the other hand, tend towards white to off-white in color and are made by coating a non-woven fiberglass scrim. Insulation facers, whether GRF or CGF, are the same color on both sides of the board.

Adhering single-ply membranes to roofing boards, such as insulation boards is common practice and is becoming a more preferred method of roof installation. Each adhesive has its own requirements in terms of “setup time”. In other words, the adhesive has to flash-off, get to string time, etc. before the membrane can be adhered to the insulation. The setup time can vary dramatically based on the ambient environmental conditions (e.g., air temperature, insulation/membrane temperature, humidity, sunlight/solar energy, etc.) on the rooftop.

SUMMARY OF THE INVENTION

When the ambient environmental conditions create longer than desired adhesive setup times, a darker-colored surface or facer has the ability to absorb the sun's radiant energy and help to speed up the setup times. Transferring the sun's radiant energy to the roofing board outer surface produces several outcomes, including, but not limited to, warmer facer temperature and increased drying potential, ultimately leading to reduced adhesive setup times.

When the ambient environmental conditions create shorter than desired adhesive setup times, a lighter-colored surface or facer has the ability to reflect the sun's radiant energy and help to slow them down. Reflecting the sun's radiant energy from the surface produces several outcomes, including, but not limited to cooler facer temperatures and reduced drying potential, ultimately leading to extended adhesive setup times.

In an embodiment, the present invention provides a roofing board, such as a foam board insulation product, with surfaces on one side of the board and on the other side of the board having different light absorption characteristics. The sides of the board referenced are the two largest surface area sides of the six-sided board, generally described as the top and bottom. The varying light absorption characteristics of the surfaces would allow the end-user to choose the side of the board most appropriate for the ambient environmental conditions at any given time on the jobsite.

In an embodiment, the present invention provides a roofing board, such as a foam board insulation product, with a lighter surface on one side of the board and a darker surface on the other side of the board. For purposes of describing the surface color/hue differences, one side of the board would have a surface color darker than, for example, Pantone® Cool Gray 5 and the other side would have a color lighter than Pantone® Cool Gray 5. The surface differences can also be described in terms of relative reflectivity, which results in potential temperature differences based on which surface is exposed to the sun.

The objects and advantages of present will be further appreciated in light of the following detailed descriptions and drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of the present invention; and

FIG. 2 is a cross-sectional view broken away, showing the insulation board of FIG. 1 covered with a roofing membrane.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention provide a roofing board, such as an insulation board, particle board, gypsum board and the like, with two exposed surfaces with different colors, one lighter than the other. An embodiment of the present invention is described below with reference to a foam insulation board, but embodiments of the present invention may include any roofing board.

As shown in FIG. 1, an insulation board 10 is provided, having a first outer planar surface 11, a second opposed outer planar surface 12, with a foam insulation layer 13 separating the two. Surfaces 11 and 12 are facers, typically used in foam insulation boards. However, facer-less foam boards or other facer-less boards can also be used. The facers can be, for example, Glass Reinforced Felt or Coated Glass Faced. The foam insulation layer 13 can be any foam typically employed for insulation purposes and, in particular, roofing insulation purposes. The foam can be, polyisocyanurate foam, or extruded (XPS) or expanded (EPS) polystyrene. However, embodiments of the present invention are not limited to the particular foam or the particular facing material.

The surfaces 11 and 12 of board 10 have different light absorbing characteristics. The difference in light absorbing characteristics may be expressed in a variety of characteristics including, without limitation, surface color, surface reflectivity, and surface temperature compared to ambient temperature. In one aspect, one surface, for example surface 11, is lighter in color than the other surface, for example surface 12. For example, surface 11 may be lighter than Pantone® Cool Gray 5, whereas surface 12 is darker than Pantone® Cool Gray 5. In another aspect, one surface, for example surface 11, has a higher solar reflectance than the other surface, for example surface 12 (e.g., as determined by ASTM E1918). For example, surface 11 may have a solar reflectance of 45% or greater, whereas surface 12 may have a solar reflectance of 8% or lower. The solar reflectance of the surfaces 11, 12 may be varied based on, for example, the coloring agents used on surfaces 11, 12. For example, coloring agents (e.g. pigments, dyes, etc.) utilized for surface 12 allow the darker facer to absorb the sun's energy, while the coloring agents utilized for surface 11 allow the lighter facer to reflect the sun's energy. In another aspect, when each surface is exposed to the sun, one surface, for example surface 11, may be cooler than the ambient temperature while the other surface, for example surface 12, may be warmer than ambient temperature. For example, surface 11 may be at or below ambient temperature when exposed to the sun. The temperature of surface 11 may be, for example, 5° F. or more below ambient temperature or between 5° F. and 10° F. below ambient temperature. For another example, surface 12 may be above ambient temperature when exposed to the sun. The temperature of surface 12 may be, for example, 30° F. or more above ambient temperature or between 30° F. and 45° F. above ambient temperature. When used in a roofing system, the different light absorbing characteristics of the surfaces 11 and 12 facilitate proper installation of a roof membrane.

As shown in FIG. 2, surface 12 of board 10 is positioned on a roof deck (not shown). Board 10 can be affixed to the roof deck in a variety of different manners and is typically mechanically fastened or adhered to the roof deck. A membrane layer 14 is then adhered to, in this case, surface 11 of board 10 with an adhesive layer 16. The membrane layer 14 can be any membrane typically used for roofing applications. These are typically polymeric membranes and can include, for example, EPDM, PVC, TPO elastomer, as well as many others. Typically, built-up roofs based on hot applied asphaltic material would not be utilized in the present invention. The adhesive layer 16 can be any adhesive typically used to apply the selected membrane to the board 10.

As indicated, surface 11 provides a lighter surface, which does not absorb as much heat as would surface 12, if exposed to the sun. Thus, when a roof is installed in the summer with hotter temperatures, exposing surface 11 upwardly in contact with the adhesive layer 16 will keep the temperature of the adhesive lower, allowing it to cure properly. Because the temperature of the surface 11 may be at or lower than it would be if it were absorbing energy from the sunlight, the time for the adhesive layer 16 to cure is increased compared to a configuration where the surface temperature is significantly above the ambient temperature due to the sunlight. This may provide additional working or “open” time before the membrane layer 14 must be positioned on the adhesive layer 16 in the final position. When adhering membrane layer 14 to surface 11 compared to surface 12, an increase in the “tack-free” time, or the time before adhesive layer 16 becomes tacky, may be 10% or greater, 25% or greater, 40% or greater, between 10% and 55%, or between 25% and 55%.

Alternately, surface 12 could be the upper surface to which the membrane layer 14 is adhered. This surface 12 would be the upper layer when the ambient temperature is lower than desirable for the particular adhesive application where the cure time would be longer than desirable. When the ambient temperature is relatively cold, the time for the adhesive layer 16 to cure when membrane layer 14 is adhered to surface 12 is reduced compared to a configuration where the surface temperature of board 10 is at or below the ambient temperature. In other words, surface 12 will absorb more heat from the sun, raising the outer temperature of board 10 and, again, facilitating adhesion of the membrane layer 14 to the surface 12 with adhesive layer 16. When adhering membrane layer 14 to surface 12 compared to surface 11, a reduction in the “tack-free” time, or the time before adhesive layer 16 becomes tacky, may be 10% or greater, 25% or greater, 40% or greater, between 10% and 55%, or between 25% and 55%.

Thus, embodiments of the present invention allow a roofing installer to choose which surface of the roofing board to expose while installing a roof, thus affecting the temperature of the adhesive and, accordingly, the cure time as the membrane layer 14 is adhered to board 10. The actual increase or decrease in cure time may be dependent on the ambient temperature, UV index, cloud cover, wind speed, and humidity. For example, the decrease in cure time when membrane layer 14 is adhered to surface 12 may be reduced due to significant cloud cover.

Roofing boards according to embodiments of the present invention may be used regardless of whether a membrane is adhered or otherwise mechanically fastened to the roofing board. For example, in an aspect of the present invention, use of the board 10 may decrease the installation time for a thermoplastic polyolefin (TPO) roofing membrane irrespective of the membrane attachment method. In that regard, a TPO membrane is often unrolled on a roof before being adhered or otherwise attached. TPO membranes, which are less supple than other membranes (e.g., EPDM and PVC), require time to unwind and adjust to the shape of the roof. When a TPO membrane is applied to surface 12 of board 10, the increased surface temperature may reduce the shape adjustment time of the TPO membrane. Accordingly, the overall installation time may be reduced.

While specific embodiments have been described in considerable detail to illustrate the present invention, the description is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept: 

What is claimed is:
 1. A generally planar roofing board comprising a first planar surface and a second planar surface, wherein light absorption characteristics of said first planar surface are different than light absorption characteristics of said second planar surface.
 2. The board claimed in claim 1 wherein said first planar surface is lighter in color than said second planar surface.
 3. The board claimed in claim 1 wherein said first planar surface is lighter than Pantone Cool Gray 5 and second planar surface is darker than Pantone Cool Gray
 5. 4. The board claimed in claim 1 wherein a first solar reflectance of said first planar surface is greater than a second solar reflectance of said second planar surface.
 5. The board claimed in claim 3 wherein the first solar reflectance is greater than or equal to 45% and the second solar reflectance is less than or equal to 8%.
 6. The board claimed in claim 1 wherein when exposed to sunlight, a temperature of said first planar surface is at or below an ambient temperature.
 7. The board claimed in claim 1 wherein when exposed to sunlight, a temperature of said second planar surface is above an ambient temperature.
 8. The board claimed in claim 1 wherein said board is fixed to a roof deck and a roofing membrane is adhered to one of said first and second planar surfaces.
 9. The board claimed in claim 8 wherein said roofing membrane is adhered to the first planar surface using an adhesive and a tack-free time of the adhesive is increased by 10% or greater compared to when the roofing membrane is adhered to the second planar surface.
 10. The board claimed in claim 8 wherein said roofing membrane is adhered to the second planar surface using an adhesive and a tack-free time of the adhesive is reduced by 10% or greater compared to when the roofing membrane is adhered to the first planar surface.
 11. The board claimed in claim 1 wherein said board is a foam insulation board.
 12. A method of applying a roof surface, wherein a foam insulation board is fixed to a roof deck; wherein said foam insulation board is a generally planar foam board having a first planar surface and a second planar surface; wherein light absorption characteristics of said first planar surface are different than light absorption characteristics of said second planar surface, said method comprising: fixing said foam insulation board to said roof deck, wherein one of said first and second planar surfaces are exposed to the atmosphere, providing an exposed surface; and adhering or attaching a roofing membrane to said exposed surface.
 13. The method claimed in claim 12 wherein said first planar surface is lighter in color than said second planar surface.
 14. The method claimed in claim 13 wherein said first planar surface is lighter than Pantone Cool Gray 5 and second planar surface is darker than Pantone Cool Gray
 5. 15. The method claimed in claim 12 wherein a first solar reflectance of said first planar surface is greater than a second solar reflectance of said second planar surface.
 16. The method claimed in claim 15 wherein the first solar reflectance is greater than or equal to 45% and the second solar reflectance is less than or equal to 8%.
 17. The method claimed in claim 12 wherein when exposed to sunlight, a temperature of said first planar surface is at or below an ambient temperature.
 18. The method claimed in claim 12 wherein when exposed to sunlight, a temperature of said second planar surface is above an ambient temperature.
 19. The method claimed in claim 12 wherein the first planar surface is exposed to the atmosphere and a tack-free time of an adhesive used to adhere the membrane is increased by 10% or greater compared to when the second planar surface is exposed to the atmosphere.
 20. The method claimed in claim 12 wherein the second planar surface is exposed to the atmosphere and a tack-free time of an adhesive used to adhere the membrane is reduced by 10% or greater compared to when the first planar surface is exposed to the atmosphere. 